Al 2 O 3 ceramics were prepared through colloidal processing and consolidation process. Initially, Al 2 O 3 powder was dispersed in aqueous medium to make 60vol% suspensions with 1.5wt% dispersant. After mixing to obtain well-dispersed slurries, a minor amount of sulfanilic acid was added and the slurries were consolidated in a nonporous mould. Al 2 O 3 green samples exhibited a homogeneous microstructure with uniform distribution in pore size. After sintering at 1600°C in air, the microstructure, hardness and toughness were characterized. Toughness as high as 6.40MPam 1/2 was obtained for Al 2 O 3 samples with sulfanic acid/Al 2 O 3 mass ratio as 5.74mg/g. Results showed that it was possible to consolidated Al 2 O 3 slurries with homogeneous microstructure and high mechanical properties.